“And Acts was most likely written by one of those “Apostles” (Luke) who mistakenly chose Matthias as an Apostle”
One must be careful of their “suppositions”, Luke wasn’t an Apostle.
Right you are my friend. My excuse? Old Age and carelessnes. :-)
I should have said Luke was among those who believed the Apostles had the God given authority to name their successors. I am not among those who believe so but, then, I am one of those "off the reservation" Unitarians. I rather think the number "12" is important and was reserved to Jesus alone.